What process should a sponsor use to gain permission from FDA for an ANDA that differs from the RLD?

To gain permission from the FDA for an Abbreviated New Drug Application (ANDA) that differs from the Reference Listed Drug (RLD), the appropriate process is through a suitability petition. A suitability petition is required when the proposed generic formulation includes controlled substances, consists of a different strength or dosage form, or utilizes a different route of administration compared to the RLD. This allows the sponsor to justify the differences and request permission to pursue an ANDA based on the unique characteristics of their product.

The suitability petition mechanism helps ensure that the FDA thoroughly evaluates the differing aspects of the new formulation and assesses its safety and efficacy in comparison to the RLD. It streamlines the path for generics while maintaining a focus on public health and safety, as the differences may impact therapeutic equivalence.

In contrast, a New Drug Application involves submitting comprehensive data to support a new drug that does not have an existing marketing application, while an Investigation Request generally pertains to inquiries for clinical trials. Compliance Notifications are mechanisms for informing the FDA about certain compliance matters, but they are not applicable for seeking approval for an ANDA that deviates from the RLD's specifications.